Try disconnecting the wire on you circuit breaker that goes to the A/C. Then reset the breaker. If it resets and stays connected, take a look at you install to see if the 12V wire has been pinched or compromised when you removed old unit and installed the new unit. Your problem is likely at the point of install rather than at the circuit protection device.
Dometic Blizzard AC Replacement
- Thread starter KTroadin
- Start date
wdk450
Well-known member
In researching your problem a I came across this DuoTherm troubleshooting document that may not apply to your model, but that notes that Dometic does NOT use a standard telephone 4 wire connection cable from the thermostat to the roof control box. It LOOKS like your standard telephone connect cable, but that has 2 wires flipped in the wiring. The Dometic version has pin 1 connecting to pin1 on the other end et cetera. Telephone cables flip pins 2 and 3, I believe. Also, I keep seeing mention of the DIP switch array on the AC control board. You might want to research what the correct settings of the DIP switches are for your application.
Did you have installation instructions with your new unit? You might want to carefully review these, since that's when your problems seemed to begin.
Good Luck!!!
Did you have installation instructions with your new unit? You might want to carefully review these, since that's when your problems seemed to begin.
Good Luck!!!
wdk450
Well-known member
Looking at the diagram on page 60 of this manual, it seems that the 12 volts DC (positive and ground) is connected to the AC control box from the furnace connector. Have you measured there?
I have looked at all these things and checked out all the mentioned above recommendations. I hooked up all connections the same as the old unit. I'm almost positive that the problem is the yellow/white and white wire have no 12 v coming through it to connect to the control box circuit board. With no 12v power the board won't supply the necessary voltage to the dometic cable (looks like phone line) to the thermostat. After the 12v line goes into the roof, I lose visible site and can't find where it goes or what it is connected too. I know it doesn't connect directly to the AC fuse because the wires coming from there are orange/white and white. I am still trying to find where the wire connects but no success so far. Thank again for all recommendations.
To all of you who helped me with all the recommendations I say thank you. I really fill so stupid at times because some of the hardest things to solve can be so simple.to accomplish. I finally found what the problem was. It was a fuse marked Rear Wall LP that was blown. Their are 17 fuses in the fuse box with one saying AC. That fuse was okay. I did check many other others like six others to see if they were giving off voltage but never checked the one that said Rear Wall LP fuse 14. Just below that is fuse 15 Fan ( ceiling fan) which was not working either. I did check that fuse earlier and it was ok. When I replaced fuse 14 and went back to the roof to check the 12 v wire it was showing 12 v. I hooked wires back up and then checked the thermostat which was working. The fan also came on. Either they mis wired the fuse panel or the fuse panel was mis numbered., who knows. Everything is working properly. Again thanks to every who helped.
CoveredWagon
Well-known member
🙂🙂🙂🙂 Glad it all worked out. Now we know who to go to for our AC problems 😉
And it didn't cost you a dime.
Robert Keene
Member
I have purchased 2 new Dometic Blizzard NXTs for my 5th wheel and I cant get them to power the thermostat either. I have 110 and 12 v and the data cable powered the old thermostat. I took an old data cable and stripped it and I have 12v coming out of the board but not lighting up the stat. I have 2 units with 2 stats and they are both on there zone 1 with the rear unit controlling the furnace. All stats light up when plugged to that unit. So I know its not the stat and all fuses are good. Kind of out of options. I took the second unit out of box to see if I just have a bad shipped unit and both do the same thing nothing. No stat power. Any thoughts? I called dometic with the original unit and these were direct placements and stats were said to work on these units.
CoveredWagon
Well-known member
Those connectors look like phone connections, but I understand they are really communication wires and connectors. Big difference.
Mr. Kean, did you get it working In your previous note you said that both stats were lighting up. That would mean they are getting power. If that is the case then you may have to reset the thermostat itself. I know on my control box I had to communication cable plugin's. You may have to switch those around also. And if that doesn't work then I agree with Mr. Hoefler and may need to replace the cables.
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